1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device and a manufacturing method of the semiconductor device. Alternatively, one embodiment of the present invention relates to an electronic device.
Note that one embodiment of the present invention is not limited to the above technical field. One embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter.
In this specification and the like, a semiconductor device indicates all the devices that can function by utilizing semiconductor characteristics. It can be said that a display device (e.g., a liquid crystal display device and a light-emitting display device), a projection device, a lighting device, an electro-optical device, a power storage device, a memory device, a semiconductor circuit, an imaging device, an electronic device, and the like include a semiconductor device in some cases.
2. Description of the Related Art
A technique in which a transistor is formed using a semiconductor thin film has been attracting attention. Such a transistor is applied to a wide range of electronic devices such as an integrated circuit (IC) and an image display device (also simply referred to as a display device). A silicon-based semiconductor material is widely known as a material for a semiconductor thin film applicable to a transistor. As another material, an oxide semiconductor has been attracting attention.
A technique in which a transistor is formed using a semiconductor thin film formed over a substrate having an insulating surface has been attracting attention.
It is known that a transistor including an oxide semiconductor has an extremely small leakage current in an off state. For example, a low-power-consumption CPU utilizing a characteristic of small leakage current of the transistor including an oxide semiconductor is disclosed (see Patent Document 1).
In addition, a technique in which oxide semiconductor layers with different electron affinities (or conduction band minimum states) are stacked to increase the carrier mobility of a transistor is disclosed (see Patent Documents 2 and 3).
In recent years, demand for an integrated circuit in which transistors and the like are integrated with high density has risen with reductions in the size and weight of an electronic device. In addition, the producibility of the semiconductor device including an integrated circuit is required to be improved.